ANDROID: GKI: virtual_device: add __drm_atomic_helper_plane_duplicate_state to the symbol list

In commit b04b6981 ("drm/virtio: New fence for every plane update"),
the virtio driver calls __drm_atomic_helper_plane_destroy_state so that
function needs to be added to the gki symbol list for the virtual device
target in order to build it properly.

Fixes: b04b6981 ("drm/virtio: New fence for every plane update")
Change-Id: If3eee2d868d82be8178ff0e22ad613a6ed215a75
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>